runtime: setg after sigFetchG

In the normal case, sigFetchG just returns the G register. But in
the case that sigFetchG fetches the G from somewhere else, the G
register still holding an invalid value. Setg here to make sure
they match.

This is particularly useful because setGsignalStack, called by
adjustSignalStack from sigtrampgo before setg to gsignal,
accesses the G register.

Should fix #35249.

Change-Id: I64c85143cb05cdb2ecca7f9936dbd8bfec186c2d
Reviewed-on: https://go-review.googlesource.com/c/go/+/204441
Reviewed-by: Ian Lance Taylor <iant@golang.org>

diff --git a/src/runtime/signal_unix.go b/src/runtime/signal_unix.go
index 5e4361e7a1bb023300a67dec4455c99c0e138303..6563186392ce4c96e7539dd0cddc2dbdc93ba85d 100644 (file)
--- a/src/runtime/signal_unix.go
+++ b/src/runtime/signal_unix.go
@@ -394,6 +394,7 @@ func sigtrampgo(sig uint32, info *siginfo, ctx unsafe.Pointer) {
        }
        c := &sigctxt{info, ctx}
        g := sigFetchG(c)
+       setg(g)
        if g == nil {
                if sig == _SIGPROF {
                        sigprofNonGoPC(c.sigpc())